9.1.2 Registers Access Permissions
Each Peripheral has different register access permissions depending on the
following:
- Its PAC Security Attribution (Secure or Non-Secure)
- If it is a Mix-Secure Peripheral: PAC, NVMCTRL, PORT, EIC, EVSYS
- If it is an Always Secure Peripheral: IDAU
- If it is an Always Non-Secure Peripheral: DSU
Peripherals excluding Mix-Secure Peripherals case:
- If the peripheral is configured
as Non-Secure in the PAC:
- Secure access and Non-Secure access are granted
- If the peripheral is configured
as Secure in the PAC:
- Secure access is granted
- Non-Secure access is discarded (Write is ignored, read 0x0) and a PAC error is triggered
Always Secure Peripheral case (IDAU) :
- Secure access is granted
- Non-Secure access is discarded (Write is ignored, read 0x0) and a PAC error is triggered
Always Non-Secure Peripheral case (DSU):
- Secure access and Non-Secure access are granted
Mix-Secure Peripherals case (PAC, NVMCTRL, PORT, EIC,
EVSYS):
- If the peripheral is configured
as Non-Secure in the PAC:
- Secure access and Non-Secure access are granted
- If the peripheral is configured
as Secure in the PAC:
- The peripheral behaves like a Mix-Secure peripheral
For more details, refer to Peripherals Security Attribution.